The Hang Seng Index fell 2.6 per cent to 24,595.54 as of 9.44am local time. The Hang Seng Tech Index dropped 2.4 per cent.
On the mainland, the CSI 300 Index slid 1.8 per cent and the Shanghai Composite Index retreated 2 per cent.
Laopu Gold tumbled 7.5 per cent to HK$566 and Zijin Mining Group lost 5.6 per cent to HK$32.52 as bullion prices declined. Alibaba Group Holding fell 2.8 per cent to HK$120.20 and Tencent Holdings slid 1.5 per cent to HK$500.50.
With the US-Israel war on Iran entering its fourth week, US President Donald Trump issued a 48-hour ultimatum to Iran to reopen the Strait of Hormuz or face strikes on its power plants. Iran responded that any such attack would trigger retaliation by closing the waterway indefinitely and targeting US and Israeli energy infrastructure across the Gulf region.
Other major Asian markets all fell. Japan’s Nikkei 225 shed 3.9 per cent, while South Korea’s Kospi retreated 4.5 per cent and Australia’s S&P/ASX 200 lost 0.8 per cent.